The present invention relates to a method of manufacturing a thin-film magnetic head and the structure thereof, and more particularly relates to a method for patterning a magnetic film constituting a magnetic core and the structure of a thin-film magnetic head obtained by using the patterning method.
The structure of an active region or element portion of a thin-film magnetic head is shown briefly in FIG. 1, and the method of manufacturing a thin-film magnetic head is generally described in the following.
In particular, a substrate 1 is formed with an under layer 2 thereupon, and a lower magnetic layer 3, a gap material 4, a conductor coil 5, an insulation layer 6, and an upper magnetic layer 7 are in this order respectively formed and etched to lay one upon another. After forming a passivation layer 8, a block including a thin-film magnetic head is cut out and subjected to necessary molding processings.
Among the above manufacturing processes, the processes for patterning the lower magnetic layer 3 and the upper magnetic layer 7 are required to have a satisfactory accuracy of dimension. In addition, it is required to make the track widths of the upper and lower magnetic layers as equal as possible, which layers appear in a finished magnetic head at a plane facing a recording medium, and also to attain a sufficient dimensional accuracy for the upper magnetic layer 7 so as to locate it entirely upon the lower magnetic layer 3. The improvement of those dimension accuracies is required particularly for a high recording density magnetic head of the type having the improved density of recording tracks.
In the method for patterning a magnetic material heretofore in use (U.S. Pat. No. 4,219,855), upper and lower magnetic layers are independently patterned and formed in a superposing relation to each other. Therefore, as shown in FIG. 2, at the plane of a front gap portion facing the medium, in order to make the upper magnetic layer 7 lay completely upon the lower magnetic layer 3, the upper track width W.sub.1 of the lower magnetic layer 3 has been designed to be larger than the lower track width W.sub.2 of the upper magnetic layer 7 by the order of 3 to 4.mu., taking into consideration the alignment allowance and dimension allowance.
The magnetic head fabricated by the above method, however, has a larger track width of the lower magnetic layer 3 than the effective track width W.sub.2. As a result, for example, if the magnetic head is utilized for a magnetic disk, recording signals in adjacent tracks are picked up as noises through the lower magnetic layer 3 so that a problem of degrading the S/N ratio arises.